Basic knowledge of fastener products:
When it comes to screws, the standard typically includes the product name (standard), material, strength grade, specification, and surface treatment. Understanding these elements is essential for selecting the right fastener for your application.
1. In terms of product type, hex head screws provide higher torsional force compared to slotted or Allen head screws. When using screws with nuts, it's generally recommended to select a screw one grade higher than the nut. This ensures better performance and cost-effectiveness in most cases.
2. Regarding material grades, our Hongyi screws mainly use carbon steel. The different carbon content levels determine the strength and hardness. For example, C1008 corresponds to a 4.8 grade, C1035 to 8.8, C1045 to 10.9, and SCM435 to 12.9 or 45H. The higher the carbon content, the harder the material becomes. Screws rated at 8.8 and above are considered high-strength fasteners.
3. For specifications like M4x8, the 'M4' refers to the outer diameter of the thread, which is 4mm, while '8' indicates the effective length embedded into the material, which is 8mm. Countersunk screws usually include the total length, while half-countersunk screws add half the head length. Pan head screws do not include the head size in their overall dimensions.
4. Heat treatment plays a crucial role in enhancing the properties of screws. When the same material is heat-treated, higher hardness often means lower toughness. Screws rated at 8.8 and above require heat treatment to ensure uniform hardness throughout. Self-tapping screws, on the other hand, undergo carburizing, where a carbon layer is applied to the surface, making it very hard while keeping the core soft. If the carburization process is incorrect, the screw may become brittle or even burn during treatment.
5. It’s important to note that when the hardness exceeds 32HRC, there is a risk of hydrogen embrittlement during plating. This occurs when hydrogen ions penetrate the metal during pickling, forming bubbles inside. These bubbles can cause the screw to fracture within 24 hours after installation. To prevent this, dehydrogenation is necessary after electroplating for such high-hardness fasteners.
MECAIR Type Pulse Valve Diaphragm
NINGBO DOTEC is a pulse Valve Diaphragm manufacturer and supplier in China for many years. We have various diaphragms for MECAIR pulse valves. Pls just tell us your Pulse Valve model or diaphragm model, then we will check it out and offer you price accordingly.
Different Options:
1. Diaphragm Sheet Material: NBR, EPDM, FKM, TPE, TPEE, HYTREL, etc
2. Diaphragm Seat Material: NBR, EPDM, FKM, Nylon, TPE, TPEE, PTFE, etc
3. Suitable Pulse Valve Size: from 1/2'' to 4''
4. Customization: If you have a drawing or can provide a sample, we can make the same diaphragm as yours
MECAIR Diaphragm, MECAIR Pulse Valve Diaphragm, MECAIR Pulse Valve Membrane
NINGBO DOTEC AUTOMATION CO., LTD , https://www.ningbodotec.com